Technologies for 3-D display in real space mainly include, among others, spatially 3-D holographic display and spatially 3-D volumetric display. In contrast to a parallax type of 3-D display, the two types of 3-D display are 3-D display in real space, and can be viewed with naked eye in the 360-degree angles. Spatially 3-D holographic display, however, requires a high-resolution, high-speed spatial light modulator in terms of dynamic display, and the technical requirement for reconstructing dynamic 3-D holographic image cannot be met currently. For spatially 3-D volumetric display technology, a main problem of missing occlusion exists for spatial 3-D display, since addressing and display is performed in a display real space. How to realize a 3-D display technology that has a real spatial sense and is achievable with currently available technologies, and can overcome the problem of missing occlusion in spatially 3-D volumetric display, would be technically crucial.